Technical Field
The present invention relates to a cleaning blade, a process cartridge and an Image forming apparatus.
Description of the Related Art
Conventionally, in electrophotographic image forming apparatuses, extraneous matters such as unnecessary residual toners after toner images are transferred to transfer papers and intermediate transferers, which adhere to the surfaces of image bearers (hereinafter referred to as “photoconductors”, “electrophotographic photoconductors” and “electrostatic latent image bearers”) to be cleaned are removed by cleaners.
As a cleaning member of the cleaner, a strip-shaped cleaning blade is well known because of having simple constitution and good cleanability. A base end of the cleaning blade is fixed on a rigid holder and an edge ridgeline thereof is pressed against the circumferential surface of the image bearer to data and scrape off a toner remaining on the image bearer.
Further, an almost spherical polymerization toner having a small particle diameter has been used in image forming apparatuses recently to produce high quality images. The polymerization tuner has higher transferability than conventional pulverization tuners. However, the polymerization toner is difficult to fully remove from the surface of the image bearer, resulting, in poor cleaning. This is because the spherical polymerization toner having a small particle diameter scrapes from the narrowest gap between the blade and the image bearer.
A contact pressure between the image bearer and the cleaning blade needs increasing to prevent the toner from scraping front the gap. However, when the contact pressure is increased, a friction between an image bearer 123 and a cleaning blade 62 in FIG. 7A increases, the cleaning blade 62 is drawn in a travel direction of the image bearer 123, and an edge 62c of the cleaning blade 62 turns over. The cleaning blade 62 turned over occasionally makes noises when restored to its original state, resisting turning over. Further, when the cleaning continues while the edge 62c of the cleaning blade 62 is turned over, a local abrasion is made a few μm from the edge 62c of an proximal face 62a of the cleaning blade 62 as shown in FIG. 7B. When the cleaning continues further, the local abrasion becomes large and finally the edge 62c is chipped as shown in FIG. 7C. When the edge 62c lacks, a toner cannot normally be removed, resulting in poor cleaning. 62b in FIGS. 7A to 7C is an undersurface of the cleaning blade.